Murray will benefit from retirement: Nadal

Rafael Nadal says he can understand Andy Murray's situation going into the first grand slam of 2019

Rafael Nadal believes Andy Murray's looming retirement is the correct move for his mental health, revealing the psychological toll of his own injury battles as he eyes off a return to Australian Open glory in the twilight of his career.

An injury-wrecked Murray has conceded the season-opening major at Melbourne Park starting on Monday could be his last before he retires.

Murray, who hopes to play through until Wimbledon but is no certainty to do so, has battled a chronic hip injury for much of the past two years.

Nadal has himself been plagued by injuries and required ankle surgery in November which forced him to relinquish his world No.1 ranking.

Speaking ahead of his bid for an 18th grand slam title - and first at Melbourne Park since 2009 - Nadal paid tribute to his longtime rival and said while he had never reached such a tipping point, he could relate to Murray's struggles.

"I am a positive guy. I always had the feeling that we'll fix it," the world No.2 said.

"But of course there are periods of time that you don't see the light. It's tough.

"My only goal has always been keep going. Even if a lot of days you go on court when you have troubles or you go to the gym without having a real goal or without knowing why I am going there, because I don't see a benefit ... you keep going.

"Probably (Murray) is fighting to keep going since a long time. If he doesn't feel that the thing can go better, probably he does the right thing for his mental health."

After withdrawing from the Brisbane International with a thigh strain and not playing a sanctioned event in four months, Nadal's sole warm-up came during two matches of Fast4 action against Nick Kyrgios on Monday night.

The 32-year-old only finished one hard court tournament last year - winning the Rogers Cup in Toronto - but insisted he was primed for another Australian Open tilt.

"If I am not feeling good, I will not be here," Nadal declared.

"Of course after surgery, after months without competing and having troubles to practice, of course there is always issues when you come back.

"But nothing new for me. I had couple of (injuries) like this. Just accept the challenges the body presents and the tennis presents."

Determined to continue evolving his game, Nadal expects to unveil a new serve during Monday's first-round clash with Australian wildcard James Duckworth.

"The serve was always a thing that I tried to improve, and I think I did," the Spaniard said.

"If I am able to make that happen in a good way, that hopefully will give me the chance to help my game (in the) longer term."